Motor control.



E. L. GALE, s3.

MOTOR CONTROL.

APPLICATION FILED NOV. 8, 1910.

1,069,060, Patented July 29, 1913;

' J M Lame I v gvwentoz as u UNITED STATES PATENT OFFICE.

ERNEST L. GALE, sn, F YONKERS, N W YORK, ASSIGNOR T0 OTIS ELEVATOR COMPANY, OEJERSEY CITY. NEW JERSEY, A ooRroRA'rIoNoENEw JERSEY.

MOTOR CONTROL.

Specificationbf Letters Patent.

Patented July 29, 1913.

Application filed November 8, 1910. Serial No. 591,271;

-.State of New York, have invented a new' and useful Improvement in Motor Control,

of which-the following is a specification.

My invention relates to a system of control and has forone of its objects the prevention of arcing at'the contacts of the-reversing switch.

Another object is to prevent the operati'on of the reversing switches inrapid succession. v

Ether objects will appear hereinafter.

The accompanying drawing illustrates my invention as emplo ed inasystem of control foran electric e evator.

In this drawing is shown a motor M, its brake B, a traction drum D, cable 6, a car Grand counterweight Vt.

The controlling apparatus comprises a potential switch P, controller switch K, reversing switches R, R, accelerating mag- .net A, fast speed magnet F, final accelerating magnet E, stop magnet S, and auxiliary stop .magnet X. Current is supplied through mains designated and ro-actuate the motor M a hand lever 11 Q of the controlling switch K is turned to the right or left of a central or stop position toenergize-either reversin switch R or B. When a reversing switch is closed, the brakeB is lifted and the motor is impelled in a proper direction. To increase the speed of the motor the hand lever is turned farther in the same direction and the fast-speed magnet F,1the accelerating magnet A and the final accelerating magnet E are energized and operated in the order named.

The auxiliary stop magnet X is in the common connection leading to the two reversing switch magnet windings and its contacts 12 are separated to break the connection for the stop magnet S whenever either reversing switch is energized. In stopping the motor, the stop magnet S is energized as soon as the hand lever 11 is returned to a central position, and a back contact 13 on one of the stop magnet contacts prevents a circuit being closed through a reversing switch as long as the stop magnet 1s energized. These'reversing switches are of the type joined by a. rocking arm adapted to press one switch down on the lower or back 'is energized.

contacts when the other-switch is energized and making connection with the top contacts, and to allow only one switch to rest on the lower contacts when neither switch There are three fields for the motor M; a ser es field in two sections, one, having the terminals 41 and 42, and the other having theterminals 42 and 43; a shunt field with the terminals 43 and 44; and an extra field in the car C is thrown over,say to the left,

a circuit is completed from the negative main by way of conductor 19, contact 20, contact segment 21, contact 22,- conductor 23, winding 24:, conductor 25, auxiliary stop .85 with the terminals 44 and 45which is en'ermagnet winding 26, conductor 27, contacts 28, 13, conductor 29,- lead 14 to the:positive main through-the potentialswitch contacts. This circuit causes the reversing switch magnet R and the auxiliary stop X to be energized and operated. As soon as the reversing switch is closed, an energizing circuit is closed for the brake B through the auxiliary contacts Not the reversing switch, and an armature circuit for the motor which is traced from the positive magnet lead 14 through the upper contacts 30 of the reversing switch, and by way of the switches R, R, and conductor 31 to the lower contact 32 of the latter switch, thence by. contact 33, conductor 34 to and through the motor armature and by way of conductor 35, contacts 36-, 37, conductor 38, through the entire starting resistance 39, conductor 40, to terminal 41, thence through the motor series field to terminal 43, andby way of lead 18 to the negative main. The shunt field of the motor receives current as S0011 as a reversing switch is closed, by way of negative lead 18, to terminal 43, through the shunt field to terminal 44, and thence by conductor 46 to and through the reversing switch contacts 30 to the positive lead 14. e

To accelerate the motor M the handlever 11 is turned farther in the same direcseparated, the main contacts 51 and the auxiliary contacts 52 and 53 are joined. The main contacts 51 short circuit a portion of the starting resistance 39 to the point 1, and the auxiliary contacts lose a circuit from the point 10 of the starting resistance by way of conductor 54, contacts 52, 53, conductors 55, '56, contacts 57, 58, conductor 59, through the accelerating magnet winding, thence byway of conductors 46 and 31 to and through the reversing switch back contacts to one side of the motor armature. It is seen that the winding of the accelerating magnet A is connected in series with a portion (from the point 1 to point 10) of the starting resistance 39, across the motor armature and is subject to the voltage at the armature terminals. The accelerating magnet operates successively to short-circuit portions of the starting resistance, the last contact 60, the series field from terminals 41 to 42 and carries an auxiliary contact 61 which in its closed position makes connectionwith contact 62, and closes a circuit connection from conductor 52 by way of contacts'62, 61., conductors 63, 64, through the final accelerating magnet winding 65, thence by wayof conductor 66 to conductor 46. This causes the final accelerating magnet E to be energized and operated, separating the contact 57 from contact 58 and'joining it with contact 67, thus opening thecircuit of the accelerating magnet A and establishing a holding circuit for the magnet'E by way of conductor 56, contacts 57, 67, and conductor 64, from the conductor through the magnet winding 65. Joining the final accelerating magnet contacts 68, short circuits the entire starting resistance 39 and the series field of the motor impressing the full voltage of the mains upon the motor armature. This circuit is, traced from the positive main by way of mainlead 14, through upper contacts of reversing switch R and lower contact of reversing switch R, conductor 34 to and through the motorvarmature, by conductor 35, contacts 36, 37 conductors 38, 69, contacts 68,'1nain lead 18 to the negative main.

To stop the motor the hand lever 11 is returned to central position, the fast speed magnet F, the accelerating magnet E, theauxiliarystop magnet X and the reversing switch B being deen'ergized in the order named. The auxiliary stop magnet contacts 12 being joined cause'a circuit to be closed through the winding of'the stop magnet S across the motor armature, the motor now acting as a generator. A circuit' is also closed through the extra -field of the motor and the extra field resistance in series ning and from conductor 46 to contact 44 through the extra field winding to contact 45, thence by conductor 74 through resistance 70 to conductor 73, thence to the armatureterminal. The stop magnet S now beingenergized by current from the motor raises its contacts in succession to short-circuit portions of the extra field resistance 70. The back contact 13 is attached to one of' the stop magnet contacts and when they are raised, the contact 13 breaks connection with the fixed contact 28, thus opening the path common-to the auxiliary stop and reversing switch windings. As long as the stop magnet S is sufliciently energized to hold the back contact 13 up, neither reversing switch can be energized. "The effect of this is to prevent the motor being energized in the same or a reverse direction too soon after thecurrent supply to the motor is cut oil" and until the dynamic braking eflect has been reduced to zero or nearly to "zero. A result is to prevent dangerous arcing at the contacts of the reversing switches at the time when the motor is reversed. -Without this arrangement it might happen that ifan attempt were made suddenly to reverse the direction of the motor, there would be a rush of current at higher potential than ordinarily employed at the contacts of one of'th'e reversing switches. This causes arcing of the contacts, sometimes flashingover which is very dangerous and destructive, and'should be avoided as much as'possible'. The connection of the armature-circuit must not be changed when the motor acts-first as a motor and then as a generator to constitute a dynamic brake, in the same direction of rotation, and this invention ab solutely prevents the reversal of the armatum-connections until the armature comes to rest or nearly to rest. The extra field winding assistsin bringing the motor more quickly to a stop, the energization of the stop magnet decreasing with the speed of the motor,and when it becomes reduced to a certain. limit the contacts fall back, the

hack, contact 13 making connection with the contact 28, to place the circuits and devices im-their unoperated condition.

In case the potential switch is opened the lower contacts 78, 79 are joined, the extrafield resistance 70 is short circuited by the conductors 76- and 77, through .'the said contacts, thus increasing the strength of the extra field, and the potential stop resistance 75 is inserted in the motor armature. cir-Y must becomereduced to a certain extent be fore the motor can be again actuated in the same or the opposite direction.

I desire not to be limited to the exact embodiment of my invention herein set forth,

as it is evident that those skilled in the artsto which this appertains may make various changes Iwithout departingfrom its spirit or scope.

What I claim is 1. In an electriccontrolling system, the combination of electro-responsive reversing switches, a stop magnet, a variable resistance controlled thereby and means in connection versing switch from operating after the other has been deenergized until the'stop magnet is deenergized.

2. In an electric controlling system, the combination of electro-responsive' reversing switches, a stop magnet, a variable resistance in a dynamic circuit and controlled by said stop magnet, and means inconnect-ion with the stop magnet to prevent both reversing switches from being energized after one-reversing switch has been deenergized until the stop magnet is deenergized.

3. In an electric controlling system, the combination of electro-r esponsive reversing switches, a stop magnet, a relay magnet in circuit with the reversing switch and controlling the stop magnet circuit, and means in connection with the stop magnet to open a circuit lead of the reversing switch windings when the stop magnet isenergized.

hIn an electric controlling system, the combination of electro-responsive reversing switches, sectional resistance, a stop magnet operative to short-circuit said resistance, and a back contact on the stop magnet to open the-"circuit of the reversing switch windings upon the energization of the magnet.

5. In an electric controlling system, the combination of electro responsive reversing switches, meansto energize either one of the reversing switches, a stop magnet having a circuit separate from the reversing switches, contacts in the circuit of the reversing switch windings operable by the stop magnet, and means energized simultaneously with the energization of either reversing switch winding to open the circuit of the stop magnet.

(3. The combination with a motor, of reversing switches, sectional resistance in a dynamic circuit of the motor, a stop magnet operable to variably control said resistance, mi-uus 1o energize the stop magnet before the direction of rotationof the'motor can be changed, and means in connection with the stop magnet to open a circuit lead of the reversing switch windings upon the energization of the said magnet.

7. The combination with a'motor, of reversing switch-es, a stop magnet, a back contact on the stop magnet to control the re-, versing switch magnet winding circuits, and an auxiliary stop magnet to open the stop magnet circuit when a reversing switch magnet is energized.

8. The combination with a motor, of reversing'switches having a common lead, a stop magnet, an auxiliary stop magnet in circuit with the reversing switch magnet windings, a back contact on the stop magnet to open and close the common connection to the reversing switch magnet windings, and contacts operated by the auxiliary stop magnet to open the stop magnet winding circuit when a reversing switch magnet isenergized.

.9. The combination with a motor, of reversing switches having contacts to close energizing circuits to the motor and dynamic circuits for the motor, sectional resistance in a dynamic circuit of themotor, a stop magnet for the motor'energized when the motor is being stopped and operable to variably control said resistance in accordance with the motor speed, and means in connection with the stop magnet to exclude the energizing' circuits when the stop magnet is energized.v

10. The combination with a motor, of reversing switches having contacts to close energizing circuits to the motor and stopping circuits for the motor, a stop magnet connected across the motor armature when the energizing circuits are broken, sectional resistances in parallel with said stop magnet and controlled thereby, and means in conjunction with the stop magnet to maintain the energizing circuits in open condition 'until the energization of the stop magnet reaches a prescribed limit.

11. The combination with a motor, of reversing switches having contacts to close energizing circuits'to the motor and stop-- ping circuits for the motor, a stop magnet connected across the motor aru'iature whenthe energizing circuits are broken, resistance in parallel with and coutrolledby-the stop magnet, and means in COIIJllIlCt-IOH with the stop magnet to maintain the energizing c'irconnected across the motor armature When the energizing circuits are broken, sectional resistance in parallel with the stop magnet isii and controlled thereby, and means in conjunction with the stop magnet to maintain the energizing circuits in open condition until the armature of the motor has nearly come to rest.

13. In an elevator controlling system, the combination of a motor, reversing switches therefor, a car switch for the reversing switches, a stop magnet for the motor, an

auxiliary stop magnet with its winding connected in a lead common to both reversing switch windings, means in connection with the'a'uxiliary stop magnet to open the energizing circuit of the sto magnet when a reversing switch is energized and to close the same when the reversing switch is not energized, and a back contact in conjunction with a stop magnet contact to make connection for the auxiliary stop magnet and a Copies of this patent may be obtained for reversing switch only after the stop magnet contact is released to render the car switch ineffective until the said back contact connection is made.

14. In an electric controlling system, the combination of electromagnetic reversing switches, a stop magnet, an auxiliary magnet in circuit with the reversing switch magnets, and switches in the stop magnetic circuit and the auxiliary magnet circuit and controlled respectively by the auxiliary magnet and the stop magnet.

In testimony whereof, I have signed my name to this specification in the presence of two subscribing witnesses.

ERNEST L.-GALE, Sn.

\Vitnesses EDWARD H. STEELE, C. C. CAMPBELL.

five cents each, by addressing the Commissioner of Patents. Washington, D, G. 

